1. Field of the Invention
The present invention relates generally to a slide-type mobile communication terminal having a main body and a sub-body mounted on the main body. The sub-body is movable relative to the main body in a sliding manner between the open position, where the sub-body is slid up so as to expose a part of the main body, and the closed position where the sub-body is slid down to completely cover the main body. The present invention more particularly relates to a method of improving the detection of the opening and closing of the terminal.
2. Description of the Related Art
Recently the portable mobile communication terminal such as mobile phone, Personal Communication Service (PCS), and Personal Digital Assistant (PDA) has undergone significant changes and modifications in design and functions in order to meet the user's various needs and desires in addition to the basic communication function. Conventionally, the design of the mobile communication terminal has been changed from the bar-type exposing the keypad through the flip and fold types with a cover protecting the keypad and finally to the slide-type.
Referring to FIG. 1 for illustrating a conventional slide-type mobile communication terminal having a main body and a sub-body, the closing of the terminal is made by sliding the sub-body completely down over the main body as shown in FIG. 1A. The opening is performed by sliding the sub-body completely up the main body as shown in FIG. 1B. As shown in the drawing, the conventional slide-type detects the opening and closing by means of a single Hall sensor 110. The Hall sensor is provided in the main body with a battery attached thereto, and a magnetic field generating element 100 in the sub-body with a speaker and a display part.
In operation, if the sub-body is slid up the main body from the position as shown in FIG. 1A to the position as shown in FIG. 1B, the Hall sensor 110 cannot be affected with the magnetic field of the magnetic field generating element 100, thus generating a high signal delivered to a control unit, such as a CPU (not shown). Receiving the high signal, the control unit recognizes the opening of the terminal indicating the sub-body has slid up the main body.
In such a conventional slide-type, if an unwanted magnetic field (caused by a foreign matter such as a snap magnet button attached to a case for enclosing the mobile communication terminal) occurs around the Hall sensor, the Hall sensor may produce an error signal causing the terminal to operate abnormally. Such a foreign magnetic field does not significantly affect a folder-type with the Hall sensor arranged toward the center, but significantly affects the slide-type with the Hall sensor arranged toward the outside to avoid the metallic slide hinge. Namely, as the Hall sensor is arranged toward the outside, the possibility of its being exposed to a foreign magnetic field is increased.
Moreover, in order to prevent the terminal from operational changes when the sub-body is not completely slid up or down the main body, the magnetic field generating element such as a magnet is designed to have a length about half the sliding distance. If the magnet has a shorter length, the effective range of the magnetic field becomes narrower, so that the slide-type terminal operates in a way sensitive to a small movement of the sub-body.
As described above, the conventional slide-type terminal has a single Hall sensor attached as far toward the outside as possible, which is easily exposed to a foreign magnetic field and may cause abnormal operation. In addition, since the magnet provided in the sub-body has a length about half the sliding distance, the length of the magnet is increased proportional to the length dimension of the terminal, thus increasing the risk of the magnet being broken at its center.